. >> leon panetta says the u.s. is facing a threat equivalent to 9/11. it will be carried out by computer. he describes a cyber pearl harbor. david martin has the story. >> reporter: u.s. officials say a cyber attack against the world's largest oil producer has been traced to hackers inside iran. another volley in an increasingly high stakes war going on in cyber space. defense secretary panetta warns potential enemies are developing the capability to launch devastating attacks. >> the collective result of these kinds of attacks could be a cyber pearl harbor. an attack that would cause physical destruction and the loss of life. an attack that would paralyze and shock the nation. and create a new profound sense of vulnerability. >> reporter: iran does not have that kind of capability yet. but u.s. officials say several recent cyber attacks have been traced to hackers inside iran. panetta stopped short of blaming iran but in a speech last night described the cyber attack which occurred two months ago. >> more than 30,000 computers that it infected were ren